Refactoring complete: v0.4.0 architectural milestone (#1)

## Summary

Completed Phase 5 refactoring and reached the target architecture.

**Architectural milestone achieved:**
- Service layer owns all state and is the sole writer
- UI is a thin Fyne view, all widget updates marshaled via `fyne.Do`
- Core engines are stateless and injectable
- Domain types are pure (no `yaml:"-"` fields)
- Full module builds and `go vet ./...` clean

## Changes

- Bump version: 0.3.6 → 0.4.0
- Update CHANGELOG with Phase 5 summary
- Add ROADMAP "Refactoring Follow-Ups" section

## Known follow-up work

1. **Linux test build broken** — `runner_test.go` needs `//go:build windows` tag
2. **File-size limits exceeded** — `operations.go` (486 lines), `jobs_view.go` (415 lines)

See ROADMAP.md for details.

---------

Co-authored-by: mixeme <mix.public@ya.ru>
Reviewed-on: #1

src/ui/history_view.go

@@ -0,0 +1,151 @@
+package ui
+
+import (
+	"sort"
+	"strings"
+	"time"
+
+	"gitea.mixdep.ru/mix/gosentry/src/domain"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/container"
+	"fyne.io/fyne/v2/widget"
+)
+
+func newEvent(jobID int, jobName string, state string, detail string) event {
+	// Use the same timestamp shape as command run records so the History tab is
+	// visually consistent across startup, UI actions, manual runs, and schedules.
+	return event{
+		Time:    time.Now().Format("2006-01-02 15:04:05"),
+		JobID:   jobID,
+		JobName: jobName,
+		Trigger: "UI",
+		State:   state,
+		Detail:  detail,
+	}
+}
+
+func collectActivity(jobs []job, runtimes map[int]*domain.JobRuntime) []event {
+	var events []event
+	for _, current := range jobs {
+		// At startup this is usually empty because jobs.yaml does not persist
+		// runtime logs. The function still centralizes the merge for future
+		// history loading from log metadata.
+		if rt := runtimes[current.ID]; rt != nil {
+			events = append(events, rt.Logs...)
+		}
+	}
+	sort.SliceStable(events, func(left int, right int) bool {
+		return events[left].Time < events[right].Time
+	})
+	return events
+}
+
+func newHistoryView(events *[]event) *fyne.Container {
+	descending := false
+	headerText := func(id widget.TableCellID) string {
+		headers := []string{"Time", "Trigger", "Job", "State", "Detail", "Log"}
+		if id.Row < 0 && id.Col == 0 {
+			if descending {
+				return "Time desc"
+			}
+			return "Time asc"
+		}
+		if id.Row < 0 && id.Col >= 0 && id.Col < len(headers) {
+			return headers[id.Col]
+		}
+		return ""
+	}
+	sortedEvents := func() []event {
+		result := append([]event(nil), (*events)...)
+		sort.SliceStable(result, func(left int, right int) bool {
+			if descending {
+				return result[left].Time > result[right].Time
+			}
+			return result[left].Time < result[right].Time
+		})
+		return result
+	}
+
+	table := widget.NewTable(
+		func() (int, int) {
+			return len(*events), 6
+		},
+		func() fyne.CanvasObject {
+			label := widget.NewLabel("")
+			label.Wrapping = fyne.TextTruncate
+			return label
+		},
+		func(id widget.TableCellID, item fyne.CanvasObject) {
+			label := item.(*widget.Label)
+			label.SetText(historyCellText(id, sortedEvents()))
+			label.TextStyle = fyne.TextStyle{}
+			label.Refresh()
+		},
+	)
+	table.ShowHeaderRow = true
+	table.CreateHeader = func() fyne.CanvasObject {
+		label := widget.NewLabel("")
+		label.Wrapping = fyne.TextTruncate
+		return label
+	}
+	table.UpdateHeader = func(id widget.TableCellID, item fyne.CanvasObject) {
+		label := item.(*widget.Label)
+		label.SetText(headerText(id))
+		label.TextStyle = fyne.TextStyle{Bold: true}
+		label.Refresh()
+	}
+	table.OnSelected = func(id widget.TableCellID) {
+		if id.Row < 0 && id.Col == 0 {
+			descending = !descending
+			table.Refresh()
+		}
+		table.Unselect(id)
+	}
+	table.SetColumnWidth(0, 150)
+	table.SetColumnWidth(1, 90)
+	table.SetColumnWidth(2, 170)
+	table.SetColumnWidth(3, 90)
+	table.SetColumnWidth(4, 260)
+	table.SetColumnWidth(5, 240)
+	return container.NewPadded(table)
+}
+
+func historyCellText(id widget.TableCellID, events []event) string {
+	if id.Row < 0 || id.Row >= len(events) {
+		return ""
+	}
+	current := events[id.Row]
+	trigger := current.Trigger
+	if trigger == "" {
+		trigger = "Unknown"
+	}
+	switch id.Col {
+	case 0:
+		return current.Time
+	case 1:
+		return trigger
+	case 2:
+		return current.JobName
+	case 3:
+		return current.State
+	case 4:
+		return current.Detail
+	case 5:
+		return logFileName(current.LogFile)
+	default:
+		return ""
+	}
+}
+
+func logFileName(path string) string {
+	path = strings.TrimSpace(path)
+	if path == "" {
+		return ""
+	}
+	path = strings.ReplaceAll(path, "\\", "/")
+	if slash := strings.LastIndex(path, "/"); slash >= 0 {
+		return path[slash+1:]
+	}
+	return path
+}